High frequency tuned oscillatory circuit



Nov. 3, 1942. A' "s, KocH A, 2,301,163

HIGH FREQUENCY TUNED oscILLAToRY C'IRCUIT .Filedruay 14, 1941 l IMlNvgN-ron ATTORNEY Patented Nov. 3, 1942 UNITED ASTATI-:s PATENT oFFlcE2,301,163 L i man mamut/'mman oscnm'rony surnamnerlm, GermanyAIienPropertyOnstodian :vestedinthe Ammann my 14, 1941, serai No.393,311 In Germany February 24, 1940 io (ci. 17a-44) shifting thereof inlongitudinal or axial direction results in very coarse adjustment, whilerotation about this axis results in regulation'which is accomplishableby very fine steps by adjustment ofthe capacity.

vIi; has been suggested in the prior art of tank circuits to provide ascrew in the shell of the tank circuit positioned at right angles to thelongitudinal axis of the tank 'circuit and to use the same (by variationof its distance to the axis of the tank circuit) for varying the meanwaverotor vane. The position of the arrester means which may be 'changedis determined empirically.

The drawing shows, by'way of example, an embodiment of the tank'circuithere disclosed. Fig. 1 is a median section taken through the tankcircuit of the invention, while Fig. 2 is a top view of the vane.

Fitted into the cylinder a -are the metallic covers or lids (endplates)` b, the latter being provided with bearings c for journaling therotor member d of the tank circuit.i

Cylinder a has a lateral' opening with a tuybular extensionl a in whicha bush h is supported. Journaled in ball bearings h' in the latter is ashaft i. Fitted on one end of the shaft i by means of a clip i' is a-scale knob or the' like indicated atk, while at the other end isattached a vane m.` In the ,position indicated by solid line in Fig. l,the said vane m occupies a position just overthe gap e, while the otherextreme position of the said vane m is indicated length of the tankcircuit. However, what has heretofore been lacking is a chance to shiftthe frequency band ofthe tank circuit by a definite amount by a simpleswitch motion. This result is attained, according to the invention, bythe agency of a pivotal plate which ismounted vanefashion on a shaftsupported at right angles to of being adjusted by turning the shaft anangle of 180, so that in the position above the gap the initial capacityand in the other position the inductance is varied. Incidentally, anincrease in the capacity moceeds parallel to an increase in theinductance, and vice versa, with the result that the adjustability ofthe vane is increased.

The shaft which supports the vane is adjustable in longitudinaldirection for the purpose of insuring a rather coarse setting-of theshifting range. AThe surface of the vane itself is wholly or partlyhelical in shape and of such dimensions that the fiat portion of thesaid vane serves for coarse adjustment on up and down movement, whereasthe other part thereof, being of oblique or twisted surface form, isused for ne settings on turning the vane as aresult of a change inposition of the helical surface in respect to the gap. In manufacture,the vane suitably is made as part of a helix.

The laterally extending shaft of thevane is turned by the agency ofaknob which hasyielding lugsY which engage in arrester means provided onthe shell of the tank circuit in order the axis of the, tank circuit andwhich is capable by the dash-lines. l

Bush h is shiftable in the tubular extension a so that the vane m may bewithdrawn more or less from the gap e. 0n a scale o to be mounted on theshell a, the setting of the bush with shaft i may be read. Longitudinalmovement of the shaft i serves for the coarse adjustment of thetankcircuit, while-fine tuning is effected by -turning the shaft i. posethe knob k is provided with yielding lugs s which engage in adjustablearrester means r on thefiange of the bush h, the said means r beingpreferably ascertained empirically in the test shop. As a result, thefrequencies for the tank circuit of the invention can be xed with adegree of accuracy heretofore unattainable.

For'flne tuning, the outer surface of the vane may preferably be dividedinto two parts. One part indicated at t, for instance, (the part nearthe shaft i) is fiat, whereas the rest is made helical. In this way nesetting in respect' to Vthe gap e is feasible by turning the shaft-i acertain angle. If the surface of the vane m were perfectly planarthroughout, no substantial change of the capacity would be brought aboutbyturning through this angle.

The Vnew tank circuit here disclosed is capable of coarse adjustment bythe shifting of the bush g with the shaftvi and the movement can be'read oii' on the scale o. Once this has ,been accomplished, turning ofthe shaft i is accom-- plished with the scale k. In the initial Dart ofthis movement coarse. adjustment is obtained,-

to iix once and for all definite positions of the but as rotation proedsthe helical surface por- For this pur-

